Recently, the National Quality Forum (NQF) endorsed 26 standardized measures of ambulatory care for national priority conditions the AQA "starter set"). Nevertheless, measurement and reporting on the quality of care delivered by office-based ambulatory care physicians has lagged. The implementation of electronic health records (EHRs) could revolutionize ambulatory quality measurement by increasing the validity of clinical measures and reducing the cost and burden of data collection. The Massachusetts E-health Collaborative is currently implementing community-wide interoperable EHRs in three Massachusetts communities. The Massachusetts Health Quality Partners (MHQP) is currently developing EHR-based quality measure specifications and data extraction logic for the AQA ambulatory quality measure set. The goal of this project is to evaluate the readiness of structured EHR data to support ambulatory clinical quality measurement by using the AQA ambulatory care measurement set to compare quality measurement based on a structured EHR data measurement method to two standard measurement methods: (1) a "hybrid method," combining claims data with medical record review, and (2) a "claims-only" method based on claims data aggregated across commercial health plans and the Medicare program. Specific Aim 1: For measures in the AQA ambulatory care measurement set, we will recruit a cohort of adult ambulatory patients from three communities that are piloting community-wide implementation of structured electronic health records (EHRs) to compare a quality measurement method based on a structured EHR data to a hybrid method involving a combination of aggregated claims data and medical record review. Specific Aim 2: For measures in the AQA ambulatory care measurement set, using two secondary data sets on adult and pediatric patients in the same three communities, we will compare a measurement method based on structured EHR data to a "claims-only method" based on a novel database that aggregates claims data from commercial health plans and Medicare. As the United States attempts to enable the national quality measurement vision outlined by the Institute of Medicine, the proposed demonstration and evaluation project will provide an urgently needed summary of the current strengths and weaknesses of structured clinical EHR data for support implementation of national standardized ambulatory quality measures. This project will also identify and prioritize the high-impact, short and long-term modifications to community-wide, office-based EHR systems that could support and accelerate the dissemination of ambulatory clinical quality measurement. [unreadable] [unreadable] [unreadable] [unreadable]